The continental ice sheets of the Pleistocene Epoch (ca. 2.6 million–11,700 years before present) did not reach what is now the southeastern United States. The colder climate in the higher Appalachians of North America during this period, however, supported plant communities that were quite different from the broad-leafed forests that currently dominate the region. Conifers and other cold-tolerant species populated areas south of the glaciers’ terminus at the height of glaciation. Warmer temperatures during subsequent millennia have caused these communities in the Southern Appalachians to contract to the cooler habitats provided by the highest peaks. Today, small areas of lush forests of red spruce (Picea rubens) and Fraser fir (Abies fraseri) cling to several dozen southern Appalachian summits >5,500 feet (1,676 m). These spruce-fir forests resemble communities now found at higher latitudes (e.g., New England and southern Quebec), making the current “islands” of red spruce and Fraser fir some of the most unique and vulnerable, ecosystems in the southeastern United States.

Fig. 1. Southern Appalachian Mountains Declining Forests

The red spruce-Fraser fir (RSFF) forests of the southern Appalachian Mountains are considered one of the most endangered ecosystems in North America. Industrial logging, pollution, and invasive species have transformed the structure and composition of RSFF forests during the past century. In fact, RSFF forests are much less extensive today than during the late 19th century. Land managers and scientists are concerned about the resilience and vigor of the community, as human activities have altered ecological processes necessary for the health and persistence of these relict forests. The RSFF forest community only exists in disjunct “island” populations at high elevations in the southern Appalachian Mountains. Several endangered species live in RSFF forests, including the Carolina northern flying squirrel, spruce-fir moss spider, Roan Mountain bluet (a perennial herb in the coffee family) and rock gnome lichen.

Fig. 2. Mt. LeConte, Tennessee (Permission of Mark Spond)

Human disturbance during the 19th, 20th, and 21st centuries has negatively affected the health of RSFF forests. Large-scale logging practices and burning led to substantial soil erosion across the Appalachians during the late 1800s and early 1900s. The economic value of red spruce lumber during the early 1900s encouraged extensive logging, often with little consideration of long-term ecological impacts. RSFF forests were clear cut in portions of what would later become The Great Smoky Mountain National Park of Tennessee and North Carolina, the Balsam Mountains, the Black Mountains, Grandfather Mountain, the Plott Balsams and Roan Mountain in North Carolina and Mount Rogers in Virginia. Decades of research and monitoring suggest that RSFF forests are often replaced by broad-leafed species following logging, particularly on south-facing aspects.

Fig. 3. Mt. Sterling, North Carolina (Permission of Mark Spond)

Scientists first observed widespread growth decline and tree mortality in RSFF forests during the 1950s. The balsam woolly adelgid, an exotic insect that kills mature Fraser fir trees, has periodically infested RSFF forests in the southern Appalachian Mountains since the middle of the 20th century. In addition, mortality rates for mature Fraser fir trees remain high due to the negative affects of anthropogenic pollution (e.g., acid precipitation). Continued scientific research and monitoring will be needed to assess the health and distribution of RSFF forests in the face of contemporary and future threats. Hopefully, such efforts will result in the protection of these relict forests and the unique insights they provide about the dynamics of forests in the southeastern United States during the past 12,000 years.

(Editors’ Note: Ironically, while the Fraser fir, along with the red spruce, is in trouble in its natural ecosystem, the Fraser fir is cultivated in huge numbers on tree farms in the higher Appalachian Mountains above 2,800 feet (850 m). Environmental conditions above this elevation hardly approach the natural habitat requirements of the Fraser fir. The Fraser fir has become the Cadillac of Christmas trees, shipped all over North America and beyond. After being cut as early as November, these trees are durable for a month or more, retaining both their needles and color. The amount of labor and pesticides, however, required to maintain the health of these trees in large monocultures, particularly at lower elevations than the trees’ natural ecosystems, makes Fraser firs the most expensive holiday trees on the market. Therefore, Fraser firs in their natural ecosystem are in decline, while the number of Fraser firs proliferating on Christmas tree farms is increasing.)

Co-editors are Neal Lineback, Appalachian State University Professor Emeritus of Geography, and Geographer Mandy Lineback Gritzner. Geography in the NewsTM is solely owned and operated by Neal Lineback for the purpose of providing geographic education to readers worldwide.

Comments

Tanya moaikel

October 15, 2013, 7:10 pm

Trees are decreasing in population because of polution natural disasters forest fires and because we cut too many down. Most of these effects usually are caused by humans. We can help stop this by making sure we don’t polite any areas by not littering also we can not cut down so many trees And grow more so that there are more trees.

warrenhoob

Switzerland

October 15, 2013, 5:00 am

The geographical location of these high mountains is superb for the business of dedicated mountain guides, and the threats to the ecosystem will also pose threats to their business.

Ava Brackney

October 14, 2013, 8:47 pm

People can highly effect the number of trees in forests. Pollution and deforestation are some ways the population of trees can decrease. Natural disasters also effect the number of trees as well.

Joseph Corless

October 14, 2013, 8:34 pm

The reason that the trees are decreasing are pollution and invasive species. Some ways to help prevent the decrease of the trees are to cut back on cutting them down to supply us with Christmas trees. Another possibility is introducing a new species the would help decrease the number of balsam wooly adelgid, but would not hurt the trees in the process.

Zena Moaikel

Woodhaven,Michigan

October 14, 2013, 8:07 pm

Humans are killing these trees by interfering with their habitat. This also kills different organisms living in or around these trees. These trees are also dying because of pollution in that area. We can prevent these res from dying by making sure no humans come contact with these trees and cut the down for their own use. We also need to make sure we are regrowing new trees in place of the dead ones.

William Fredrick

October 14, 2013, 3:56 pm

What about blocking off land for those trees so that are human ways would not harm as easily.

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